The mysterious howl may mean “I’m a wolf, and I’m over here,” or “Go away—you’re not welcome here!” You’ll have a better idea of what to do after browsing this beautiful, photo-heavy piece by Ray Ford, complete with hair-raising wolf recordings. He writes:

The roots of the public wolf howl reach back to the late 1950s, when biologist Douglas Pimlot was trying to locate wolves concealed in the park’s dense bush. Pimlott played recorded howls on truck-mounted speakers and listened for the response. The broadcasts received an almost instant—and unnerving—reply. The air filled with howls.